A week ago, Seedlings to Stars had a short post about the state of the Giants' pitching post-Wheeler.  Not much in the way of new information for most of us here, but here's a couple quotes:

With the lower minors, I think the important word is “depth.” There’s nobody there that we should be jumping up and down about, but a number of guys are having nice years. Mike Kickham, Seth Rosin, Chris Heston, Jake Dunning, Reinier Roibal, Lorenzo Mendoza, Kendry Flores…somebody in that group is going to work out, just because of the sheer number of guys there. But there’s nobody in that group that is blowing everybody away or wowing scouts. Most likely, San Francisco gets a couple of back-of-the-rotation or middle relief/setup options out of that bunch.

Escobar, Blackburn, and Gregorio also get shout-outs.

They're not very high on Wheeler, either:

As far as Wheeler goes, I’ve always fallen more in the cautious camp. I think the guy is going to be a major league pitcher, but given that his secondary stuff isn’t particularly well-developed and his control has never been very good, it’s an open question as to whether he becomes a #2 starter, Jonathan Sanchez-esque erratic #3/4/5 starter, a power closer, or just a fastball-oriented setup guy. At his age, it’s far too early to make the call on which direction he’ll take–he may figure out the control and develop his secondary pitches, or he may not. Given how high the attrition rates on pitching prospects are, and also that his control is already a major issue in the low minors, Wheeler was far from a sure thing.

That said, I’m not a huge believer in Wheeler as a prospect for the same reasons Nathaniel mentioned. When you read a scouting report on Zack’s secondary stuff you run across adjectives like “functional” and “consistent” but you never see much mention in the way of potential or upside for those pitches. He’s going to have to show me something more, especially in AA or AAA before I change my stance on him.